Before turning his hand to fiction, Mayor wrote history books, the most notable of which concerned the lumber and oil business in Louisiana from the 1870s to the 1970s. This book was published by the University of Georgia Press and very well received.

Prior to that, Mayor—who was brought up in the US, Canada and France—was variously employed as a scholarly editor, a researcher for TIME-LIFE Books, a political advance-man, a theater photographer, a newspaper writer/editor, a lab technician for Paris-Match Magazine in Paris, France, and a medical illustrator.

In addition to writing novels and occasional articles, Mayor gives talks and workshops all around the country, including the Bread Loaf Young Writers conference in Middlebury, Vermont, and the Colby College seminar on forensic sciences in Waterville, Maine.

He is also a death investigator for Vermont’s Chief Medical Examiner, a deputy for the Windham County Sheriff’s Department, and has 25 years experience as a volunteer firefighter and EMT. Mayor’s critically-acclaimed series of police novels features Lt. Joe Gunther of the Brattleboro, Vermont police department.

The books, which have been appearing about once a year since 1988, have been published in five languages (if you count British,) and routinely gather high praise from such sources as the New York Times, the Washington Post, the Los Angeles Times, the New Yorker, and many others, often appearing on their “ten best” yearly lists.

Whereas many writers base their books on only interviews and scholarly research, Mayor's novels are based on actual experience in the field. The result adds a depth, detail and veracity to his characters and their tribulations that has led the New York Times to call him “the boss man on procedures”.